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*/ |
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package jsr166y; |
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import java.io.Serializable; |
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import java.util.*; |
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|
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import java.util.concurrent.*; |
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import java.util.concurrent.atomic.*; |
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import sun.misc.Unsafe; |
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import java.lang.reflect.*; |
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|
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import java.io.Serializable; |
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import java.util.Collection; |
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import java.util.Collections; |
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import java.util.List; |
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import java.util.RandomAccess; |
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import java.util.Map; |
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import java.util.WeakHashMap; |
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|
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/** |
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* Abstract base class for tasks that run within a {@link |
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* ForkJoinPool}. A ForkJoinTask is a thread-like entity that is much |
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* Abstract base class for tasks that run within a {@link ForkJoinPool}. |
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* A {@code ForkJoinTask} is a thread-like entity that is much |
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* lighter weight than a normal thread. Huge numbers of tasks and |
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* subtasks may be hosted by a small number of actual threads in a |
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* ForkJoinPool, at the price of some usage limitations. |
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* |
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* <p> A "main" ForkJoinTask begins execution when submitted to a |
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* {@link ForkJoinPool}. Once started, it will usually in turn start |
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* other subtasks. As indicated by the name of this class, many |
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* programs using ForkJoinTasks employ only methods {@code fork} |
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* and {@code join}, or derivatives such as |
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* {@code invokeAll}. However, this class also provides a number |
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* of other methods that can come into play in advanced usages, as |
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* well as extension mechanics that allow support of new forms of |
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* fork/join processing. |
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* <p>A "main" {@code ForkJoinTask} begins execution when submitted |
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* to a {@link ForkJoinPool}. Once started, it will usually in turn |
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* start other subtasks. As indicated by the name of this class, |
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* many programs using {@code ForkJoinTask} employ only methods |
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* {@link #fork} and {@link #join}, or derivatives such as {@link |
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* #invokeAll}. However, this class also provides a number of other |
32 |
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* methods that can come into play in advanced usages, as well as |
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* extension mechanics that allow support of new forms of fork/join |
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* processing. |
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* |
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* <p>A ForkJoinTask is a lightweight form of {@link Future}. The |
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* efficiency of ForkJoinTasks stems from a set of restrictions (that |
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* are only partially statically enforceable) reflecting their |
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* intended use as computational tasks calculating pure functions or |
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* operating on purely isolated objects. The primary coordination |
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* mechanisms are {@link #fork}, that arranges asynchronous execution, |
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* and {@link #join}, that doesn't proceed until the task's result has |
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* been computed. Computations should avoid {@code synchronized} |
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* methods or blocks, and should minimize other blocking |
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* synchronization apart from joining other tasks or using |
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* synchronizers such as Phasers that are advertised to cooperate with |
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* fork/join scheduling. Tasks should also not perform blocking IO, |
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* and should ideally access variables that are completely independent |
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* of those accessed by other running tasks. Minor breaches of these |
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* restrictions, for example using shared output streams, may be |
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* tolerable in practice, but frequent use may result in poor |
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* performance, and the potential to indefinitely stall if the number |
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* of threads not waiting for IO or other external synchronization |
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* becomes exhausted. This usage restriction is in part enforced by |
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* not permitting checked exceptions such as {@code IOExceptions} |
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* to be thrown. However, computations may still encounter unchecked |
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* exceptions, that are rethrown to callers attempting join |
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* them. These exceptions may additionally include |
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* RejectedExecutionExceptions stemming from internal resource |
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* exhaustion such as failure to allocate internal task queues. |
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* <p>A {@code ForkJoinTask} is a lightweight form of {@link Future}. |
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* The efficiency of {@code ForkJoinTask}s stems from a set of |
38 |
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* restrictions (that are only partially statically enforceable) |
39 |
> |
* reflecting their intended use as computational tasks calculating |
40 |
> |
* pure functions or operating on purely isolated objects. The |
41 |
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* primary coordination mechanisms are {@link #fork}, that arranges |
42 |
> |
* asynchronous execution, and {@link #join}, that doesn't proceed |
43 |
> |
* until the task's result has been computed. Computations should |
44 |
> |
* avoid {@code synchronized} methods or blocks, and should minimize |
45 |
> |
* other blocking synchronization apart from joining other tasks or |
46 |
> |
* using synchronizers such as Phasers that are advertised to |
47 |
> |
* cooperate with fork/join scheduling. Tasks should also not perform |
48 |
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* blocking IO, and should ideally access variables that are |
49 |
> |
* completely independent of those accessed by other running |
50 |
> |
* tasks. Minor breaches of these restrictions, for example using |
51 |
> |
* shared output streams, may be tolerable in practice, but frequent |
52 |
> |
* use may result in poor performance, and the potential to |
53 |
> |
* indefinitely stall if the number of threads not waiting for IO or |
54 |
> |
* other external synchronization becomes exhausted. This usage |
55 |
> |
* restriction is in part enforced by not permitting checked |
56 |
> |
* exceptions such as {@code IOExceptions} to be thrown. However, |
57 |
> |
* computations may still encounter unchecked exceptions, that are |
58 |
> |
* rethrown to callers attempting to join them. These exceptions may |
59 |
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* additionally include RejectedExecutionExceptions stemming from |
60 |
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* internal resource exhaustion such as failure to allocate internal |
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> |
* task queues. |
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* |
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* <p>The primary method for awaiting completion and extracting |
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* results of a task is {@link #join}, but there are several variants: |
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* execute other tasks while awaiting joins, which is sometimes more |
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* efficient but only applies when all subtasks are known to be |
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* strictly tree-structured. Method {@link #invoke} is semantically |
71 |
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* equivalent to {@code fork(); join()} but always attempts to |
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* begin execution in the current thread. The "<em>quiet</em>" forms |
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* of these methods do not extract results or report exceptions. These |
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* equivalent to {@code fork(); join()} but always attempts to begin |
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* execution in the current thread. The "<em>quiet</em>" forms of |
73 |
> |
* these methods do not extract results or report exceptions. These |
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* may be useful when a set of tasks are being executed, and you need |
75 |
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* to delay processing of results or exceptions until all complete. |
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* Method {@code invokeAll} (available in multiple versions) |
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* performs the most common form of parallel invocation: forking a set |
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* of tasks and joining them all. |
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* |
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* <p> The ForkJoinTask class is not usually directly subclassed. |
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* <p>The execution status of tasks may be queried at several levels |
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* of detail: {@link #isDone} is true if a task completed in any way |
82 |
> |
* (including the case where a task was cancelled without executing); |
83 |
> |
* {@link #isCompletedNormally} is true if a task completed without |
84 |
> |
* cancellation or encountering an exception; {@link #isCancelled} is |
85 |
> |
* true if the task was cancelled (in which case {@link #getException} |
86 |
> |
* returns a {@link java.util.concurrent.CancellationException}); and |
87 |
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* {@link #isCompletedAbnormally} is true if a task was either |
88 |
> |
* cancelled or encountered an exception, in which case {@link |
89 |
> |
* #getException} will return either the encountered exception or |
90 |
> |
* {@link java.util.concurrent.CancellationException}. |
91 |
> |
* |
92 |
> |
* <p>The ForkJoinTask class is not usually directly subclassed. |
93 |
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* Instead, you subclass one of the abstract classes that support a |
94 |
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* particular style of fork/join processing. Normally, a concrete |
94 |
> |
* particular style of fork/join processing, typically {@link |
95 |
> |
* RecursiveAction} for computations that do not return results, or |
96 |
> |
* {@link RecursiveTask} for those that do. Normally, a concrete |
97 |
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* ForkJoinTask subclass declares fields comprising its parameters, |
98 |
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* established in a constructor, and then defines a {@code compute} |
99 |
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* method that somehow uses the control methods supplied by this base |
100 |
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* class. While these methods have {@code public} access (to allow |
101 |
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* instances of different task subclasses to call each others |
101 |
> |
* instances of different task subclasses to call each other's |
102 |
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* methods), some of them may only be called from within other |
103 |
|
* ForkJoinTasks (as may be determined using method {@link |
104 |
|
* #inForkJoinPool}). Attempts to invoke them in other contexts |
105 |
|
* result in exceptions or errors, possibly including |
106 |
|
* ClassCastException. |
107 |
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* |
108 |
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* <p>Most base support methods are {@code final} because their |
109 |
< |
* implementations are intrinsically tied to the underlying |
110 |
< |
* lightweight task scheduling framework, and so cannot be overridden. |
111 |
< |
* Developers creating new basic styles of fork/join processing should |
112 |
< |
* minimally implement {@code protected} methods |
113 |
< |
* {@code exec}, {@code setRawResult}, and |
114 |
< |
* {@code getRawResult}, while also introducing an abstract |
115 |
< |
* computational method that can be implemented in its subclasses, |
116 |
< |
* possibly relying on other {@code protected} methods provided |
98 |
< |
* by this class. |
108 |
> |
* <p>Most base support methods are {@code final}, to prevent |
109 |
> |
* overriding of implementations that are intrinsically tied to the |
110 |
> |
* underlying lightweight task scheduling framework. Developers |
111 |
> |
* creating new basic styles of fork/join processing should minimally |
112 |
> |
* implement {@code protected} methods {@link #exec}, {@link |
113 |
> |
* #setRawResult}, and {@link #getRawResult}, while also introducing |
114 |
> |
* an abstract computational method that can be implemented in its |
115 |
> |
* subclasses, possibly relying on other {@code protected} methods |
116 |
> |
* provided by this class. |
117 |
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* |
118 |
|
* <p>ForkJoinTasks should perform relatively small amounts of |
119 |
< |
* computations, otherwise splitting into smaller tasks. As a very |
120 |
< |
* rough rule of thumb, a task should perform more than 100 and less |
121 |
< |
* than 10000 basic computational steps. If tasks are too big, then |
122 |
< |
* parallelism cannot improve throughput. If too small, then memory |
123 |
< |
* and internal task maintenance overhead may overwhelm processing. |
119 |
> |
* computation. Large tasks should be split into smaller subtasks, |
120 |
> |
* usually via recursive decomposition. As a very rough rule of thumb, |
121 |
> |
* a task should perform more than 100 and less than 10000 basic |
122 |
> |
* computational steps. If tasks are too big, then parallelism cannot |
123 |
> |
* improve throughput. If too small, then memory and internal task |
124 |
> |
* maintenance overhead may overwhelm processing. |
125 |
> |
* |
126 |
> |
* <p>This class provides {@code adapt} methods for {@link Runnable} |
127 |
> |
* and {@link Callable}, that may be of use when mixing execution of |
128 |
> |
* {@code ForkJoinTasks} with other kinds of tasks. When all tasks |
129 |
> |
* are of this form, consider using a pool in |
130 |
> |
* {@linkplain ForkJoinPool#setAsyncMode async mode}. |
131 |
|
* |
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* <p>ForkJoinTasks are {@code Serializable}, which enables them |
133 |
< |
* to be used in extensions such as remote execution frameworks. It is |
134 |
< |
* in general sensible to serialize tasks only before or after, but |
135 |
< |
* not during execution. Serialization is not relied on during |
111 |
< |
* execution itself. |
132 |
> |
* <p>ForkJoinTasks are {@code Serializable}, which enables them to be |
133 |
> |
* used in extensions such as remote execution frameworks. It is |
134 |
> |
* sensible to serialize tasks only before or after, but not during, |
135 |
> |
* execution. Serialization is not relied on during execution itself. |
136 |
|
* |
137 |
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* @since 1.7 |
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* @author Doug Lea |
269 |
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synchronized (this) { |
270 |
|
try { |
271 |
|
while (status >= 0) { |
272 |
< |
long nt = nanos - System.nanoTime() - startTime; |
272 |
> |
long nt = nanos - (System.nanoTime() - startTime); |
273 |
|
if (nt <= 0) |
274 |
|
break; |
275 |
|
wait(nt / 1000000, (int) (nt % 1000000)); |
390 |
|
|
391 |
|
/** |
392 |
|
* Returns result or throws exception using j.u.c.Future conventions. |
393 |
< |
* Only call when {@code isDone} known to be true. |
393 |
> |
* Only call when {@code isDone} known to be true or thread known |
394 |
> |
* to be interrupted. |
395 |
|
*/ |
396 |
|
private V reportFutureResult() |
397 |
< |
throws ExecutionException, InterruptedException { |
397 |
> |
throws InterruptedException, ExecutionException { |
398 |
> |
if (Thread.interrupted()) |
399 |
> |
throw new InterruptedException(); |
400 |
|
int s = status & COMPLETION_MASK; |
401 |
|
if (s < NORMAL) { |
402 |
|
Throwable ex; |
404 |
|
throw new CancellationException(); |
405 |
|
if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null) |
406 |
|
throw new ExecutionException(ex); |
380 |
– |
if (Thread.interrupted()) |
381 |
– |
throw new InterruptedException(); |
407 |
|
} |
408 |
|
return getRawResult(); |
409 |
|
} |
414 |
|
*/ |
415 |
|
private V reportTimedFutureResult() |
416 |
|
throws InterruptedException, ExecutionException, TimeoutException { |
417 |
+ |
if (Thread.interrupted()) |
418 |
+ |
throw new InterruptedException(); |
419 |
|
Throwable ex; |
420 |
|
int s = status & COMPLETION_MASK; |
421 |
|
if (s == NORMAL) |
422 |
|
return getRawResult(); |
423 |
< |
if (s == CANCELLED) |
423 |
> |
else if (s == CANCELLED) |
424 |
|
throw new CancellationException(); |
425 |
< |
if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null) |
425 |
> |
else if (s == EXCEPTIONAL && (ex = exceptionMap.get(this)) != null) |
426 |
|
throw new ExecutionException(ex); |
427 |
< |
if (Thread.interrupted()) |
428 |
< |
throw new InterruptedException(); |
402 |
< |
throw new TimeoutException(); |
427 |
> |
else |
428 |
> |
throw new TimeoutException(); |
429 |
|
} |
430 |
|
|
431 |
|
// internal execution methods |
510 |
|
/** |
511 |
|
* Arranges to asynchronously execute this task. While it is not |
512 |
|
* necessarily enforced, it is a usage error to fork a task more |
513 |
< |
* than once unless it has completed and been reinitialized. This |
514 |
< |
* method may be invoked only from within ForkJoinTask |
515 |
< |
* computations (as may be determined using method {@link |
516 |
< |
* #inForkJoinPool}). Attempts to invoke in other contexts result |
517 |
< |
* in exceptions or errors, possibly including ClassCastException. |
513 |
> |
* than once unless it has completed and been reinitialized. |
514 |
> |
* Subsequent modifications to the state of this task or any data |
515 |
> |
* it operates on are not necessarily consistently observable by |
516 |
> |
* any thread other than the one executing it unless preceded by a |
517 |
> |
* call to {@link #join} or related methods, or a call to {@link |
518 |
> |
* #isDone} returning {@code true}. |
519 |
> |
* |
520 |
> |
* <p>This method may be invoked only from within {@code |
521 |
> |
* ForkJoinTask} computations (as may be determined using method |
522 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
523 |
> |
* result in exceptions or errors, possibly including {@code |
524 |
> |
* ClassCastException}. |
525 |
> |
* |
526 |
> |
* @return {@code this}, to simplify usage |
527 |
|
*/ |
528 |
< |
public final void fork() { |
528 |
> |
public final ForkJoinTask<V> fork() { |
529 |
|
((ForkJoinWorkerThread) Thread.currentThread()) |
530 |
|
.pushTask(this); |
531 |
+ |
return this; |
532 |
|
} |
533 |
|
|
534 |
|
/** |
535 |
< |
* Returns the result of the computation when it is ready. |
536 |
< |
* This method differs from {@code get} in that abnormal |
537 |
< |
* completion results in RuntimeExceptions or Errors, not |
538 |
< |
* ExecutionExceptions. |
535 |
> |
* Returns the result of the computation when it {@link #isDone is done}. |
536 |
> |
* This method differs from {@link #get()} in that |
537 |
> |
* abnormal completion results in {@code RuntimeException} or |
538 |
> |
* {@code Error}, not {@code ExecutionException}. |
539 |
|
* |
540 |
|
* @return the computed result |
541 |
|
*/ |
548 |
|
|
549 |
|
/** |
550 |
|
* Commences performing this task, awaits its completion if |
551 |
< |
* necessary, and return its result. |
551 |
> |
* necessary, and return its result, or throws an (unchecked) |
552 |
> |
* exception if the underlying computation did so. |
553 |
|
* |
517 |
– |
* @throws Throwable (a RuntimeException, Error, or unchecked |
518 |
– |
* exception) if the underlying computation did so |
554 |
|
* @return the computed result |
555 |
|
*/ |
556 |
|
public final V invoke() { |
561 |
|
} |
562 |
|
|
563 |
|
/** |
564 |
< |
* Forks both tasks, returning when {@code isDone} holds for |
565 |
< |
* both of them or an exception is encountered. This method may be |
566 |
< |
* invoked only from within ForkJoinTask computations (as may be |
567 |
< |
* determined using method {@link #inForkJoinPool}). Attempts to |
568 |
< |
* invoke in other contexts result in exceptions or errors, |
569 |
< |
* possibly including ClassCastException. |
570 |
< |
* |
571 |
< |
* @param t1 one task |
572 |
< |
* @param t2 the other task |
573 |
< |
* @throws NullPointerException if t1 or t2 are null |
574 |
< |
* @throws RuntimeException or Error if either task did so |
564 |
> |
* Forks the given tasks, returning when {@code isDone} holds for |
565 |
> |
* each task or an (unchecked) exception is encountered, in which |
566 |
> |
* case the exception is rethrown. If either task encounters an |
567 |
> |
* exception, the other one may be, but is not guaranteed to be, |
568 |
> |
* cancelled. If both tasks throw an exception, then this method |
569 |
> |
* throws one of them. The individual status of each task may be |
570 |
> |
* checked using {@link #getException()} and related methods. |
571 |
> |
* |
572 |
> |
* <p>This method may be invoked only from within {@code |
573 |
> |
* ForkJoinTask} computations (as may be determined using method |
574 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
575 |
> |
* result in exceptions or errors, possibly including {@code |
576 |
> |
* ClassCastException}. |
577 |
> |
* |
578 |
> |
* @param t1 the first task |
579 |
> |
* @param t2 the second task |
580 |
> |
* @throws NullPointerException if any task is null |
581 |
|
*/ |
582 |
< |
public static void invokeAll(ForkJoinTask<?>t1, ForkJoinTask<?> t2) { |
582 |
> |
public static void invokeAll(ForkJoinTask<?> t1, ForkJoinTask<?> t2) { |
583 |
|
t2.fork(); |
584 |
|
t1.invoke(); |
585 |
|
t2.join(); |
586 |
|
} |
587 |
|
|
588 |
|
/** |
589 |
< |
* Forks the given tasks, returning when {@code isDone} holds |
590 |
< |
* for all of them. If any task encounters an exception, others |
591 |
< |
* may be cancelled. This method may be invoked only from within |
592 |
< |
* ForkJoinTask computations (as may be determined using method |
593 |
< |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
594 |
< |
* result in exceptions or errors, possibly including |
595 |
< |
* ClassCastException. |
589 |
> |
* Forks the given tasks, returning when {@code isDone} holds for |
590 |
> |
* each task or an (unchecked) exception is encountered, in which |
591 |
> |
* case the exception is rethrown. If any task encounters an |
592 |
> |
* exception, others may be, but are not guaranteed to be, |
593 |
> |
* cancelled. If more than one task encounters an exception, then |
594 |
> |
* this method throws any one of these exceptions. The individual |
595 |
> |
* status of each task may be checked using {@link #getException()} |
596 |
> |
* and related methods. |
597 |
> |
* |
598 |
> |
* <p>This method may be invoked only from within {@code |
599 |
> |
* ForkJoinTask} computations (as may be determined using method |
600 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
601 |
> |
* result in exceptions or errors, possibly including {@code |
602 |
> |
* ClassCastException}. |
603 |
|
* |
604 |
< |
* @param tasks the array of tasks |
605 |
< |
* @throws NullPointerException if tasks or any element are null |
558 |
< |
* @throws RuntimeException or Error if any task did so |
604 |
> |
* @param tasks the tasks |
605 |
> |
* @throws NullPointerException if any task is null |
606 |
|
*/ |
607 |
|
public static void invokeAll(ForkJoinTask<?>... tasks) { |
608 |
|
Throwable ex = null; |
638 |
|
} |
639 |
|
|
640 |
|
/** |
641 |
< |
* Forks all tasks in the collection, returning when |
642 |
< |
* {@code isDone} holds for all of them. If any task |
643 |
< |
* encounters an exception, others may be cancelled. This method |
644 |
< |
* may be invoked only from within ForkJoinTask computations (as |
645 |
< |
* may be determined using method {@link |
646 |
< |
* #inForkJoinPool}). Attempts to invoke in other contexts result |
647 |
< |
* in exceptions or errors, possibly including ClassCastException. |
641 |
> |
* Forks all tasks in the specified collection, returning when |
642 |
> |
* {@code isDone} holds for each task or an (unchecked) exception |
643 |
> |
* is encountered. If any task encounters an exception, others |
644 |
> |
* may be, but are not guaranteed to be, cancelled. If more than |
645 |
> |
* one task encounters an exception, then this method throws any |
646 |
> |
* one of these exceptions. The individual status of each task |
647 |
> |
* may be checked using {@link #getException()} and related |
648 |
> |
* methods. The behavior of this operation is undefined if the |
649 |
> |
* specified collection is modified while the operation is in |
650 |
> |
* progress. |
651 |
> |
* |
652 |
> |
* <p>This method may be invoked only from within {@code |
653 |
> |
* ForkJoinTask} computations (as may be determined using method |
654 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
655 |
> |
* result in exceptions or errors, possibly including {@code |
656 |
> |
* ClassCastException}. |
657 |
|
* |
658 |
|
* @param tasks the collection of tasks |
659 |
+ |
* @return the tasks argument, to simplify usage |
660 |
|
* @throws NullPointerException if tasks or any element are null |
604 |
– |
* @throws RuntimeException or Error if any task did so |
661 |
|
*/ |
662 |
< |
public static void invokeAll(Collection<? extends ForkJoinTask<?>> tasks) { |
663 |
< |
if (!(tasks instanceof List)) { |
662 |
> |
public static <T extends ForkJoinTask<?>> Collection<T> invokeAll(Collection<T> tasks) { |
663 |
> |
if (!(tasks instanceof RandomAccess) || !(tasks instanceof List<?>)) { |
664 |
|
invokeAll(tasks.toArray(new ForkJoinTask<?>[tasks.size()])); |
665 |
< |
return; |
665 |
> |
return tasks; |
666 |
|
} |
667 |
+ |
@SuppressWarnings("unchecked") |
668 |
|
List<? extends ForkJoinTask<?>> ts = |
669 |
|
(List<? extends ForkJoinTask<?>>) tasks; |
670 |
|
Throwable ex = null; |
697 |
|
} |
698 |
|
if (ex != null) |
699 |
|
rethrowException(ex); |
700 |
+ |
return tasks; |
701 |
|
} |
702 |
|
|
703 |
|
/** |
704 |
< |
* Returns true if the computation performed by this task has |
705 |
< |
* completed (or has been cancelled). |
706 |
< |
* |
707 |
< |
* @return true if this computation has completed |
708 |
< |
*/ |
709 |
< |
public final boolean isDone() { |
710 |
< |
return status < 0; |
653 |
< |
} |
654 |
< |
|
655 |
< |
/** |
656 |
< |
* Returns true if this task was cancelled. |
657 |
< |
* |
658 |
< |
* @return true if this task was cancelled |
659 |
< |
*/ |
660 |
< |
public final boolean isCancelled() { |
661 |
< |
return (status & COMPLETION_MASK) == CANCELLED; |
662 |
< |
} |
663 |
< |
|
664 |
< |
/** |
665 |
< |
* Asserts that the results of this task's computation will not be |
666 |
< |
* used. If a cancellation occurs before attempting to execute this |
667 |
< |
* task, then execution will be suppressed, {@code isCancelled} |
668 |
< |
* will report true, and {@code join} will result in a |
669 |
< |
* {@code CancellationException} being thrown. Otherwise, when |
670 |
< |
* cancellation races with completion, there are no guarantees |
671 |
< |
* about whether {@code isCancelled} will report true, whether |
672 |
< |
* {@code join} will return normally or via an exception, or |
673 |
< |
* whether these behaviors will remain consistent upon repeated |
674 |
< |
* invocation. |
704 |
> |
* Attempts to cancel execution of this task. This attempt will |
705 |
> |
* fail if the task has already completed, has already been |
706 |
> |
* cancelled, or could not be cancelled for some other reason. If |
707 |
> |
* successful, and this task has not started when cancel is |
708 |
> |
* called, execution of this task is suppressed, {@link |
709 |
> |
* #isCancelled} will report true, and {@link #join} will result |
710 |
> |
* in a {@code CancellationException} being thrown. |
711 |
|
* |
712 |
|
* <p>This method may be overridden in subclasses, but if so, must |
713 |
|
* still ensure that these minimal properties hold. In particular, |
714 |
< |
* the cancel method itself must not throw exceptions. |
714 |
> |
* the {@code cancel} method itself must not throw exceptions. |
715 |
|
* |
716 |
< |
* <p> This method is designed to be invoked by <em>other</em> |
716 |
> |
* <p>This method is designed to be invoked by <em>other</em> |
717 |
|
* tasks. To terminate the current task, you can just return or |
718 |
|
* throw an unchecked exception from its computation method, or |
719 |
< |
* invoke {@code completeExceptionally}. |
719 |
> |
* invoke {@link #completeExceptionally}. |
720 |
|
* |
721 |
|
* @param mayInterruptIfRunning this value is ignored in the |
722 |
< |
* default implementation because tasks are not in general |
722 |
> |
* default implementation because tasks are not |
723 |
|
* cancelled via interruption |
724 |
|
* |
725 |
< |
* @return true if this task is now cancelled |
725 |
> |
* @return {@code true} if this task is now cancelled |
726 |
|
*/ |
727 |
|
public boolean cancel(boolean mayInterruptIfRunning) { |
728 |
|
setCompletion(CANCELLED); |
729 |
|
return (status & COMPLETION_MASK) == CANCELLED; |
730 |
|
} |
731 |
|
|
732 |
+ |
public final boolean isDone() { |
733 |
+ |
return status < 0; |
734 |
+ |
} |
735 |
+ |
|
736 |
+ |
public final boolean isCancelled() { |
737 |
+ |
return (status & COMPLETION_MASK) == CANCELLED; |
738 |
+ |
} |
739 |
+ |
|
740 |
|
/** |
741 |
< |
* Returns true if this task threw an exception or was cancelled. |
741 |
> |
* Returns {@code true} if this task threw an exception or was cancelled. |
742 |
|
* |
743 |
< |
* @return true if this task threw an exception or was cancelled |
743 |
> |
* @return {@code true} if this task threw an exception or was cancelled |
744 |
|
*/ |
745 |
|
public final boolean isCompletedAbnormally() { |
746 |
|
return (status & COMPLETION_MASK) < NORMAL; |
747 |
|
} |
748 |
|
|
749 |
|
/** |
750 |
+ |
* Returns {@code true} if this task completed without throwing an |
751 |
+ |
* exception and was not cancelled. |
752 |
+ |
* |
753 |
+ |
* @return {@code true} if this task completed without throwing an |
754 |
+ |
* exception and was not cancelled |
755 |
+ |
*/ |
756 |
+ |
public final boolean isCompletedNormally() { |
757 |
+ |
return (status & COMPLETION_MASK) == NORMAL; |
758 |
+ |
} |
759 |
+ |
|
760 |
+ |
/** |
761 |
|
* Returns the exception thrown by the base computation, or a |
762 |
< |
* CancellationException if cancelled, or null if none or if the |
763 |
< |
* method has not yet completed. |
762 |
> |
* {@code CancellationException} if cancelled, or {@code null} if |
763 |
> |
* none or if the method has not yet completed. |
764 |
|
* |
765 |
< |
* @return the exception, or null if none |
765 |
> |
* @return the exception, or {@code null} if none |
766 |
|
*/ |
767 |
|
public final Throwable getException() { |
768 |
|
int s = status & COMPLETION_MASK; |
769 |
< |
if (s >= NORMAL) |
770 |
< |
return null; |
771 |
< |
if (s == CANCELLED) |
717 |
< |
return new CancellationException(); |
718 |
< |
return exceptionMap.get(this); |
769 |
> |
return ((s >= NORMAL) ? null : |
770 |
> |
(s == CANCELLED) ? new CancellationException() : |
771 |
> |
exceptionMap.get(this)); |
772 |
|
} |
773 |
|
|
774 |
|
/** |
777 |
|
* {@code join} and related operations. This method may be used |
778 |
|
* to induce exceptions in asynchronous tasks, or to force |
779 |
|
* completion of tasks that would not otherwise complete. Its use |
780 |
< |
* in other situations is likely to be wrong. This method is |
780 |
> |
* in other situations is discouraged. This method is |
781 |
|
* overridable, but overridden versions must invoke {@code super} |
782 |
|
* implementation to maintain guarantees. |
783 |
|
* |
797 |
|
* operations. This method may be used to provide results for |
798 |
|
* asynchronous tasks, or to provide alternative handling for |
799 |
|
* tasks that would not otherwise complete normally. Its use in |
800 |
< |
* other situations is likely to be wrong. This method is |
800 |
> |
* other situations is discouraged. This method is |
801 |
|
* overridable, but overridden versions must invoke {@code super} |
802 |
|
* implementation to maintain guarantees. |
803 |
|
* |
822 |
|
|
823 |
|
public final V get(long timeout, TimeUnit unit) |
824 |
|
throws InterruptedException, ExecutionException, TimeoutException { |
825 |
+ |
long nanos = unit.toNanos(timeout); |
826 |
|
ForkJoinWorkerThread w = getWorker(); |
827 |
|
if (w == null || status < 0 || !w.unpushTask(this) || !tryQuietlyInvoke()) |
828 |
< |
awaitDone(w, unit.toNanos(timeout)); |
828 |
> |
awaitDone(w, nanos); |
829 |
|
return reportTimedFutureResult(); |
830 |
|
} |
831 |
|
|
832 |
|
/** |
833 |
< |
* Possibly executes other tasks until this task is ready, then |
834 |
< |
* returns the result of the computation. This method may be more |
835 |
< |
* efficient than {@code join}, but is only applicable when |
836 |
< |
* there are no potential dependencies between continuation of the |
837 |
< |
* current task and that of any other task that might be executed |
838 |
< |
* while helping. (This usually holds for pure divide-and-conquer |
839 |
< |
* tasks). This method may be invoked only from within |
840 |
< |
* ForkJoinTask computations (as may be determined using method |
841 |
< |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
842 |
< |
* result in exceptions or errors, possibly including |
843 |
< |
* ClassCastException. |
833 |
> |
* Possibly executes other tasks until this task {@link #isDone is |
834 |
> |
* done}, then returns the result of the computation. This method |
835 |
> |
* may be more efficient than {@code join}, but is only applicable |
836 |
> |
* when there are no potential dependencies between continuation |
837 |
> |
* of the current task and that of any other task that might be |
838 |
> |
* executed while helping. (This usually holds for pure |
839 |
> |
* divide-and-conquer tasks). |
840 |
> |
* |
841 |
> |
* <p>This method may be invoked only from within {@code |
842 |
> |
* ForkJoinTask} computations (as may be determined using method |
843 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
844 |
> |
* result in exceptions or errors, possibly including {@code |
845 |
> |
* ClassCastException}. |
846 |
|
* |
847 |
|
* @return the computed result |
848 |
|
*/ |
854 |
|
} |
855 |
|
|
856 |
|
/** |
857 |
< |
* Possibly executes other tasks until this task is ready. This |
858 |
< |
* method may be invoked only from within ForkJoinTask |
859 |
< |
* computations (as may be determined using method {@link |
860 |
< |
* #inForkJoinPool}). Attempts to invoke in other contexts result |
861 |
< |
* in exceptions or errors, possibly including ClassCastException. |
857 |
> |
* Possibly executes other tasks until this task {@link #isDone is |
858 |
> |
* done}. This method may be useful when processing collections |
859 |
> |
* of tasks when some have been cancelled or otherwise known to |
860 |
> |
* have aborted. |
861 |
> |
* |
862 |
> |
* <p>This method may be invoked only from within {@code |
863 |
> |
* ForkJoinTask} computations (as may be determined using method |
864 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
865 |
> |
* result in exceptions or errors, possibly including {@code |
866 |
> |
* ClassCastException}. |
867 |
|
*/ |
868 |
|
public final void quietlyHelpJoin() { |
869 |
|
if (status >= 0) { |
902 |
|
|
903 |
|
/** |
904 |
|
* Possibly executes tasks until the pool hosting the current task |
905 |
< |
* {@link ForkJoinPool#isQuiescent}. This method may be of use in |
906 |
< |
* designs in which many tasks are forked, but none are explicitly |
907 |
< |
* joined, instead executing them until all are processed. |
905 |
> |
* {@link ForkJoinPool#isQuiescent is quiescent}. This method may |
906 |
> |
* be of use in designs in which many tasks are forked, but none |
907 |
> |
* are explicitly joined, instead executing them until all are |
908 |
> |
* processed. |
909 |
> |
* |
910 |
> |
* <p>This method may be invoked only from within {@code |
911 |
> |
* ForkJoinTask} computations (as may be determined using method |
912 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
913 |
> |
* result in exceptions or errors, possibly including {@code |
914 |
> |
* ClassCastException}. |
915 |
|
*/ |
916 |
|
public static void helpQuiesce() { |
917 |
|
((ForkJoinWorkerThread) Thread.currentThread()) |
924 |
|
* this task, but only if reuse occurs when this task has either |
925 |
|
* never been forked, or has been forked, then completed and all |
926 |
|
* outstanding joins of this task have also completed. Effects |
927 |
< |
* under any other usage conditions are not guaranteed, and are |
928 |
< |
* almost surely wrong. This method may be useful when executing |
927 |
> |
* under any other usage conditions are not guaranteed. |
928 |
> |
* This method may be useful when executing |
929 |
|
* pre-constructed trees of subtasks in loops. |
930 |
|
*/ |
931 |
|
public void reinitialize() { |
938 |
|
* Returns the pool hosting the current task execution, or null |
939 |
|
* if this task is executing outside of any ForkJoinPool. |
940 |
|
* |
941 |
< |
* @return the pool, or null if none |
941 |
> |
* @see #inForkJoinPool |
942 |
> |
* @return the pool, or {@code null} if none |
943 |
|
*/ |
944 |
|
public static ForkJoinPool getPool() { |
945 |
|
Thread t = Thread.currentThread(); |
946 |
< |
return ((t instanceof ForkJoinWorkerThread) ? |
947 |
< |
((ForkJoinWorkerThread) t).pool : null); |
946 |
> |
return (t instanceof ForkJoinWorkerThread) ? |
947 |
> |
((ForkJoinWorkerThread) t).pool : null; |
948 |
|
} |
949 |
|
|
950 |
|
/** |
964 |
|
* by the current thread, and has not commenced executing in |
965 |
|
* another thread. This method may be useful when arranging |
966 |
|
* alternative local processing of tasks that could have been, but |
967 |
< |
* were not, stolen. This method may be invoked only from within |
968 |
< |
* ForkJoinTask computations (as may be determined using method |
969 |
< |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
970 |
< |
* result in exceptions or errors, possibly including |
971 |
< |
* ClassCastException. |
967 |
> |
* were not, stolen. |
968 |
> |
* |
969 |
> |
* <p>This method may be invoked only from within {@code |
970 |
> |
* ForkJoinTask} computations (as may be determined using method |
971 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
972 |
> |
* result in exceptions or errors, possibly including {@code |
973 |
> |
* ClassCastException}. |
974 |
|
* |
975 |
< |
* @return true if unforked |
975 |
> |
* @return {@code true} if unforked |
976 |
|
*/ |
977 |
|
public boolean tryUnfork() { |
978 |
|
return ((ForkJoinWorkerThread) Thread.currentThread()) |
985 |
|
* value may be useful for heuristic decisions about whether to |
986 |
|
* fork other tasks. |
987 |
|
* |
988 |
+ |
* <p>This method may be invoked only from within {@code |
989 |
+ |
* ForkJoinTask} computations (as may be determined using method |
990 |
+ |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
991 |
+ |
* result in exceptions or errors, possibly including {@code |
992 |
+ |
* ClassCastException}. |
993 |
+ |
* |
994 |
|
* @return the number of tasks |
995 |
|
*/ |
996 |
|
public static int getQueuedTaskCount() { |
1008 |
|
* tasks, and to process computations locally if this threshold is |
1009 |
|
* exceeded. |
1010 |
|
* |
1011 |
+ |
* <p>This method may be invoked only from within {@code |
1012 |
+ |
* ForkJoinTask} computations (as may be determined using method |
1013 |
+ |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
1014 |
+ |
* result in exceptions or errors, possibly including {@code |
1015 |
+ |
* ClassCastException}. |
1016 |
+ |
* |
1017 |
|
* @return the surplus number of tasks, which may be negative |
1018 |
|
*/ |
1019 |
|
public static int getSurplusQueuedTaskCount() { |
1024 |
|
// Extension methods |
1025 |
|
|
1026 |
|
/** |
1027 |
< |
* Returns the result that would be returned by {@code join}, |
1028 |
< |
* even if this task completed abnormally, or null if this task is |
1029 |
< |
* not known to have been completed. This method is designed to |
1030 |
< |
* aid debugging, as well as to support extensions. Its use in any |
1031 |
< |
* other context is discouraged. |
1027 |
> |
* Returns the result that would be returned by {@link #join}, even |
1028 |
> |
* if this task completed abnormally, or {@code null} if this task |
1029 |
> |
* is not known to have been completed. This method is designed |
1030 |
> |
* to aid debugging, as well as to support extensions. Its use in |
1031 |
> |
* any other context is discouraged. |
1032 |
|
* |
1033 |
< |
* @return the result, or null if not completed |
1033 |
> |
* @return the result, or {@code null} if not completed |
1034 |
|
*/ |
1035 |
|
public abstract V getRawResult(); |
1036 |
|
|
1049 |
|
* called otherwise. The return value controls whether this task |
1050 |
|
* is considered to be done normally. It may return false in |
1051 |
|
* asynchronous actions that require explicit invocations of |
1052 |
< |
* {@code complete} to become joinable. It may throw exceptions |
1053 |
< |
* to indicate abnormal exit. |
1052 |
> |
* {@link #complete} to become joinable. It may also throw an |
1053 |
> |
* (unchecked) exception to indicate abnormal exit. |
1054 |
|
* |
1055 |
< |
* @return true if completed normally |
973 |
< |
* @throws Error or RuntimeException if encountered during computation |
1055 |
> |
* @return {@code true} if completed normally |
1056 |
|
*/ |
1057 |
|
protected abstract boolean exec(); |
1058 |
|
|
1059 |
|
/** |
1060 |
< |
* Returns, but does not unschedule or execute, the task queued by |
1061 |
< |
* the current thread but not yet executed, if one is |
1060 |
> |
* Returns, but does not unschedule or execute, a task queued by |
1061 |
> |
* the current thread but not yet executed, if one is immediately |
1062 |
|
* available. There is no guarantee that this task will actually |
1063 |
< |
* be polled or executed next. This method is designed primarily |
1064 |
< |
* to support extensions, and is unlikely to be useful otherwise. |
1065 |
< |
* This method may be invoked only from within ForkJoinTask |
1066 |
< |
* computations (as may be determined using method {@link |
1067 |
< |
* #inForkJoinPool}). Attempts to invoke in other contexts result |
1068 |
< |
* in exceptions or errors, possibly including ClassCastException. |
1063 |
> |
* be polled or executed next. Conversely, this method may return |
1064 |
> |
* null even if a task exists but cannot be accessed without |
1065 |
> |
* contention with other threads. This method is designed |
1066 |
> |
* primarily to support extensions, and is unlikely to be useful |
1067 |
> |
* otherwise. |
1068 |
> |
* |
1069 |
> |
* <p>This method may be invoked only from within {@code |
1070 |
> |
* ForkJoinTask} computations (as may be determined using method |
1071 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
1072 |
> |
* result in exceptions or errors, possibly including {@code |
1073 |
> |
* ClassCastException}. |
1074 |
|
* |
1075 |
< |
* @return the next task, or null if none are available |
1075 |
> |
* @return the next task, or {@code null} if none are available |
1076 |
|
*/ |
1077 |
|
protected static ForkJoinTask<?> peekNextLocalTask() { |
1078 |
|
return ((ForkJoinWorkerThread) Thread.currentThread()) |
1083 |
|
* Unschedules and returns, without executing, the next task |
1084 |
|
* queued by the current thread but not yet executed. This method |
1085 |
|
* is designed primarily to support extensions, and is unlikely to |
1086 |
< |
* be useful otherwise. This method may be invoked only from |
1087 |
< |
* within ForkJoinTask computations (as may be determined using |
1088 |
< |
* method {@link #inForkJoinPool}). Attempts to invoke in other |
1089 |
< |
* contexts result in exceptions or errors, possibly including |
1090 |
< |
* ClassCastException. |
1086 |
> |
* be useful otherwise. |
1087 |
> |
* |
1088 |
> |
* <p>This method may be invoked only from within {@code |
1089 |
> |
* ForkJoinTask} computations (as may be determined using method |
1090 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
1091 |
> |
* result in exceptions or errors, possibly including {@code |
1092 |
> |
* ClassCastException}. |
1093 |
|
* |
1094 |
< |
* @return the next task, or null if none are available |
1094 |
> |
* @return the next task, or {@code null} if none are available |
1095 |
|
*/ |
1096 |
|
protected static ForkJoinTask<?> pollNextLocalTask() { |
1097 |
|
return ((ForkJoinWorkerThread) Thread.currentThread()) |
1106 |
|
* {@code null} result does not necessarily imply quiescence |
1107 |
|
* of the pool this task is operating in. This method is designed |
1108 |
|
* primarily to support extensions, and is unlikely to be useful |
1109 |
< |
* otherwise. This method may be invoked only from within |
1021 |
< |
* ForkJoinTask computations (as may be determined using method |
1022 |
< |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
1023 |
< |
* result in exceptions or errors, possibly including |
1024 |
< |
* ClassCastException. |
1109 |
> |
* otherwise. |
1110 |
|
* |
1111 |
< |
* @return a task, or null if none are available |
1111 |
> |
* <p>This method may be invoked only from within {@code |
1112 |
> |
* ForkJoinTask} computations (as may be determined using method |
1113 |
> |
* {@link #inForkJoinPool}). Attempts to invoke in other contexts |
1114 |
> |
* result in exceptions or errors, possibly including {@code |
1115 |
> |
* ClassCastException}. |
1116 |
> |
* |
1117 |
> |
* @return a task, or {@code null} if none are available |
1118 |
|
*/ |
1119 |
|
protected static ForkJoinTask<?> pollTask() { |
1120 |
|
return ((ForkJoinWorkerThread) Thread.currentThread()) |
1121 |
|
.pollTask(); |
1122 |
|
} |
1123 |
|
|
1124 |
+ |
/** |
1125 |
+ |
* Adaptor for Runnables. This implements RunnableFuture |
1126 |
+ |
* to be compliant with AbstractExecutorService constraints |
1127 |
+ |
* when used in ForkJoinPool. |
1128 |
+ |
*/ |
1129 |
+ |
static final class AdaptedRunnable<T> extends ForkJoinTask<T> |
1130 |
+ |
implements RunnableFuture<T> { |
1131 |
+ |
final Runnable runnable; |
1132 |
+ |
final T resultOnCompletion; |
1133 |
+ |
T result; |
1134 |
+ |
AdaptedRunnable(Runnable runnable, T result) { |
1135 |
+ |
if (runnable == null) throw new NullPointerException(); |
1136 |
+ |
this.runnable = runnable; |
1137 |
+ |
this.resultOnCompletion = result; |
1138 |
+ |
} |
1139 |
+ |
public T getRawResult() { return result; } |
1140 |
+ |
public void setRawResult(T v) { result = v; } |
1141 |
+ |
public boolean exec() { |
1142 |
+ |
runnable.run(); |
1143 |
+ |
result = resultOnCompletion; |
1144 |
+ |
return true; |
1145 |
+ |
} |
1146 |
+ |
public void run() { invoke(); } |
1147 |
+ |
private static final long serialVersionUID = 5232453952276885070L; |
1148 |
+ |
} |
1149 |
+ |
|
1150 |
+ |
/** |
1151 |
+ |
* Adaptor for Callables |
1152 |
+ |
*/ |
1153 |
+ |
static final class AdaptedCallable<T> extends ForkJoinTask<T> |
1154 |
+ |
implements RunnableFuture<T> { |
1155 |
+ |
final Callable<? extends T> callable; |
1156 |
+ |
T result; |
1157 |
+ |
AdaptedCallable(Callable<? extends T> callable) { |
1158 |
+ |
if (callable == null) throw new NullPointerException(); |
1159 |
+ |
this.callable = callable; |
1160 |
+ |
} |
1161 |
+ |
public T getRawResult() { return result; } |
1162 |
+ |
public void setRawResult(T v) { result = v; } |
1163 |
+ |
public boolean exec() { |
1164 |
+ |
try { |
1165 |
+ |
result = callable.call(); |
1166 |
+ |
return true; |
1167 |
+ |
} catch (Error err) { |
1168 |
+ |
throw err; |
1169 |
+ |
} catch (RuntimeException rex) { |
1170 |
+ |
throw rex; |
1171 |
+ |
} catch (Exception ex) { |
1172 |
+ |
throw new RuntimeException(ex); |
1173 |
+ |
} |
1174 |
+ |
} |
1175 |
+ |
public void run() { invoke(); } |
1176 |
+ |
private static final long serialVersionUID = 2838392045355241008L; |
1177 |
+ |
} |
1178 |
+ |
|
1179 |
+ |
/** |
1180 |
+ |
* Returns a new {@code ForkJoinTask} that performs the {@code run} |
1181 |
+ |
* method of the given {@code Runnable} as its action, and returns |
1182 |
+ |
* a null result upon {@link #join}. |
1183 |
+ |
* |
1184 |
+ |
* @param runnable the runnable action |
1185 |
+ |
* @return the task |
1186 |
+ |
*/ |
1187 |
+ |
public static ForkJoinTask<?> adapt(Runnable runnable) { |
1188 |
+ |
return new AdaptedRunnable<Void>(runnable, null); |
1189 |
+ |
} |
1190 |
+ |
|
1191 |
+ |
/** |
1192 |
+ |
* Returns a new {@code ForkJoinTask} that performs the {@code run} |
1193 |
+ |
* method of the given {@code Runnable} as its action, and returns |
1194 |
+ |
* the given result upon {@link #join}. |
1195 |
+ |
* |
1196 |
+ |
* @param runnable the runnable action |
1197 |
+ |
* @param result the result upon completion |
1198 |
+ |
* @return the task |
1199 |
+ |
*/ |
1200 |
+ |
public static <T> ForkJoinTask<T> adapt(Runnable runnable, T result) { |
1201 |
+ |
return new AdaptedRunnable<T>(runnable, result); |
1202 |
+ |
} |
1203 |
+ |
|
1204 |
+ |
/** |
1205 |
+ |
* Returns a new {@code ForkJoinTask} that performs the {@code call} |
1206 |
+ |
* method of the given {@code Callable} as its action, and returns |
1207 |
+ |
* its result upon {@link #join}, translating any checked exceptions |
1208 |
+ |
* encountered into {@code RuntimeException}. |
1209 |
+ |
* |
1210 |
+ |
* @param callable the callable action |
1211 |
+ |
* @return the task |
1212 |
+ |
*/ |
1213 |
+ |
public static <T> ForkJoinTask<T> adapt(Callable<? extends T> callable) { |
1214 |
+ |
return new AdaptedCallable<T>(callable); |
1215 |
+ |
} |
1216 |
+ |
|
1217 |
|
// Serialization support |
1218 |
|
|
1219 |
|
private static final long serialVersionUID = -7721805057305804111L; |
1222 |
|
* Save the state to a stream. |
1223 |
|
* |
1224 |
|
* @serialData the current run status and the exception thrown |
1225 |
< |
* during execution, or null if none |
1225 |
> |
* during execution, or {@code null} if none |
1226 |
|
* @param s the stream |
1227 |
|
*/ |
1228 |
|
private void writeObject(java.io.ObjectOutputStream s) |
1246 |
|
setDoneExceptionally((Throwable) ex); |
1247 |
|
} |
1248 |
|
|
1249 |
< |
// Temporary Unsafe mechanics for preliminary release |
1250 |
< |
private static Unsafe getUnsafe() throws Throwable { |
1249 |
> |
// Unsafe mechanics |
1250 |
> |
|
1251 |
> |
private static final sun.misc.Unsafe UNSAFE = getUnsafe(); |
1252 |
> |
private static final long statusOffset = |
1253 |
> |
objectFieldOffset("status", ForkJoinTask.class); |
1254 |
> |
|
1255 |
> |
private static long objectFieldOffset(String field, Class<?> klazz) { |
1256 |
|
try { |
1257 |
< |
return Unsafe.getUnsafe(); |
1257 |
> |
return UNSAFE.objectFieldOffset(klazz.getDeclaredField(field)); |
1258 |
> |
} catch (NoSuchFieldException e) { |
1259 |
> |
// Convert Exception to corresponding Error |
1260 |
> |
NoSuchFieldError error = new NoSuchFieldError(field); |
1261 |
> |
error.initCause(e); |
1262 |
> |
throw error; |
1263 |
> |
} |
1264 |
> |
} |
1265 |
> |
|
1266 |
> |
/** |
1267 |
> |
* Returns a sun.misc.Unsafe. Suitable for use in a 3rd party package. |
1268 |
> |
* Replace with a simple call to Unsafe.getUnsafe when integrating |
1269 |
> |
* into a jdk. |
1270 |
> |
* |
1271 |
> |
* @return a sun.misc.Unsafe |
1272 |
> |
*/ |
1273 |
> |
private static sun.misc.Unsafe getUnsafe() { |
1274 |
> |
try { |
1275 |
> |
return sun.misc.Unsafe.getUnsafe(); |
1276 |
|
} catch (SecurityException se) { |
1277 |
|
try { |
1278 |
|
return java.security.AccessController.doPrivileged |
1279 |
< |
(new java.security.PrivilegedExceptionAction<Unsafe>() { |
1280 |
< |
public Unsafe run() throws Exception { |
1281 |
< |
return getUnsafePrivileged(); |
1279 |
> |
(new java.security |
1280 |
> |
.PrivilegedExceptionAction<sun.misc.Unsafe>() { |
1281 |
> |
public sun.misc.Unsafe run() throws Exception { |
1282 |
> |
java.lang.reflect.Field f = sun.misc |
1283 |
> |
.Unsafe.class.getDeclaredField("theUnsafe"); |
1284 |
> |
f.setAccessible(true); |
1285 |
> |
return (sun.misc.Unsafe) f.get(null); |
1286 |
|
}}); |
1287 |
|
} catch (java.security.PrivilegedActionException e) { |
1288 |
< |
throw e.getCause(); |
1288 |
> |
throw new RuntimeException("Could not initialize intrinsics", |
1289 |
> |
e.getCause()); |
1290 |
|
} |
1291 |
|
} |
1292 |
|
} |
1081 |
– |
|
1082 |
– |
private static Unsafe getUnsafePrivileged() |
1083 |
– |
throws NoSuchFieldException, IllegalAccessException { |
1084 |
– |
Field f = Unsafe.class.getDeclaredField("theUnsafe"); |
1085 |
– |
f.setAccessible(true); |
1086 |
– |
return (Unsafe) f.get(null); |
1087 |
– |
} |
1088 |
– |
|
1089 |
– |
private static long fieldOffset(String fieldName) |
1090 |
– |
throws NoSuchFieldException { |
1091 |
– |
return UNSAFE.objectFieldOffset |
1092 |
– |
(ForkJoinTask.class.getDeclaredField(fieldName)); |
1093 |
– |
} |
1094 |
– |
|
1095 |
– |
static final Unsafe UNSAFE; |
1096 |
– |
static final long statusOffset; |
1097 |
– |
|
1098 |
– |
static { |
1099 |
– |
try { |
1100 |
– |
UNSAFE = getUnsafe(); |
1101 |
– |
statusOffset = fieldOffset("status"); |
1102 |
– |
} catch (Throwable e) { |
1103 |
– |
throw new RuntimeException("Could not initialize intrinsics", e); |
1104 |
– |
} |
1105 |
– |
} |
1106 |
– |
|
1293 |
|
} |